Botulinum toxin therapy for neuropsychiatric disorders

ABSTRACT

Methods for treating psychiatric disorders include intracranial administration of a therapeutically effective amount of a neurotoxin, such as a botulinum toxin type A, to a human patient.

CROSS REFERENCE

[0001] This application is a continuation of application Ser. No.10/143,078, filed May 10, 2002, the contents of which prior filedapplication is incorporated by reference in its entirety into thiscontinuation application.

BACKGROUND

[0002] The present invention relates to methods for treatingneuropsychiatric disorders. In particular, the present invention relatesto methods for treating neuropsychiatric disorders by intracranialadministration of a neurotoxin.

[0003] Neuropsychiatric Disorders

[0004] A neuropsychiatric disorder is a neurological disturbance that istypically labeled according to which of the four mental faculties areaffected. For example, one group includes disorders of thinking andcognition, such as schizophrenia and delirium; a second group includesdisorders of mood, such as affective disorders and anxiety; a thirdgroup includes disorders of social behavior, such as character defectsand personality disorders; and a fourth group includes disorders oflearning, memory, and intelligence, such as mental retardation anddementia.

[0005] Accordingly, neuropsychiatric disorders encompass schizophrenia,delirium, Alzheimer's disease, depression, mania, attention deficitdisorders, drug addiction, dementia, agitation, apathy, anxiety,psychoses, post-traumatic stress disorders, irritability, anddisinhibition.

[0006] Schizophrenia

[0007] Schizophrenia is a disorder that affects about one percent of theworld population. Three general symptoms of schizophrenia are oftenreferred to as positive symptoms, negative symptoms, and disorganizedsymptoms. Positive symptoms may include delusions (abnormal beliefs),hallucinations (abnormal perceptions), and disorganized thinking.Hallucinations may be auditory, visual, olfactory, or tactile.

[0008] Disorganized thinking may manifest itself in schizophrenicpatients by disjointed speech and the inability to maintain logicalthought processes. Negative symptoms may represent the absence of normalbehavior. Negative symptoms include emotional flatness or lack ofexpression and may be characterized by social withdrawal, reducedenergy, reduced motivation, and reduced activity. Catatonia may also beassociated with negative symptoms of schizophrenia. The symptoms ofschizophrenia should continuously persist for a duration of about sixmonths in order for the patient to be diagnosed as schizophrenic. Basedon the types of symptoms a patient reveals, schizophrenia may becategorized into subtypes including catatonic schizophrenia, paranoidschizophrenia, and disorganized schizophrenia.

[0009] The brains of schizophrenic patients are often characterized byenlarged lateral ventricles, which may be associated with a reduction ofthe hippocampus and an enhancement in the size of the basal ganglia.Schizophrenic patients may also have enlarged third ventricles andwidening of sulci. These anatomical characterizations point to areduction in cortical tissue.

[0010] Although the cause of schizophrenia is not precisely known, thereare several hypotheses regarding the causes. One hypothesis is thatschizophrenia is associated with increased dopamine activity within thecortical and limbic areas of the brain. This hypothesis is supported bythe therapeutic effects achieved by antipsychotic drugs that blockcertain dopamine receptors. In addition, amphetamine use may beassociated with schizophrenia-like psychotic symptoms; amphetamines acton dopamine receptors.

[0011] Examples of antipsychotic drugs that may be used to treatschizophrenic patients include phenothizines, such as chlorpromazine andtrifluopromazine; thioxanthenes, such as chlorprothixene; fluphenazine;butyropenones, such as haloperidol; loxapine; mesoridazine; molindone;quetiapine; thiothixene; trifluoperazine; perphenazine; thioridazine;risperidone; dibenzodiazepines, such as clozapine; and olanzapine.Although these agents may relieve the symptoms of schizophrenia, theiradministration may also result in undesirable side effects includingParkinson's disease-like symptoms (tremor, muscle rigidity, loss offacial expression); dystonia; restlessness; tardive dyskinesia; weightgain; skin problems; dry mouth; constipation; blurred vision;drowsiness; slurred speech; agranulocytosis.

[0012] Antipsychotic drugs are believed to primarily act on dopaminereceptors with a particular affinity for the D₂, D₃, and D₄ receptors.It is believed that the D₃ and D₄ receptors may have a higher affinityfor certain antipsychotics, such as clozapine, as compared to theothers. Brains of schizophrenic patients appear to have increasednumbers of D₂ receptors in the caudate nucleus, the nucleus accumbens(ventral striatum), and the olfactory tubercule.

[0013] Dopamine neurons may be organized into four major subsystems: thetuberoinfundibular system; the nigrostriatal system; the mesolimbicsystem; and the mesocortical system. The tuberoinfundibular dopaminergicsystem originates in cell bodies of the arcuate nucleus of thehypothalamus and projects to the pituitary stalk. This system may beinvolved in secondary neuroendocrine abnormalities in schizophrenia. Thenigrostriatal dopaminergic system originates in the substantia nigra andprojects primarily to the putamen and the caudate nucleus. Themesolimbic dopaminergic system originates in the ventral tegmental areaand projects to the mesial component of the limbic system, whichincludes the nucleus accumbens, the nuclei of the stria terminalis,parts of the amygdala and hippocampus, the lateral septal nuclei, andthe mesial frontal, anterior cingulate, and entorhinal cortex. Thenucleus accumbens is a convergence site from the amygdala, hippocampus,entorhinal area, anterior cingulate area, and parts of the temporallobe. Thus, the mesolimbic dopaminergic projection may modulate andtransform information conveyed from the nucleus accumbens to the septum,hypothalamus, anterior cingulate area, and frontal lobes, and overactivemodulation of the nucleus accumbens output to these areas may contributeto positive symptoms associated with schizophrenia. The mesocorticaldopaminergic system originates in the ventral tegmental area andprojects to the neocortex and heavily to the prefrontal cortex. Thiscomponent may be important in the negative symptoms of schizophrenia.

[0014] The ventral tegmental area, which is the source of origination ofthe dopaminergic input to the nucleus accumbens, receives a cholinergicinput from the pedunculopontine nuclei of the brainstem. Thepedunculopontine nucleus provides an excitatory cholinergic input to theventral tegmental area (Clarke et al., Innervation of substantia nigraneurons by cholinergic afferents from the pedunculopontine nucleus inthe rat. Neuroanatomical and electrophysiological evidence,Neuroscience, 23:1011-1019,1987). It has been reported thatschizophrenic patients have an increased number of cholinergic neuronsin the pedunculopontine nuclei (Garcia-Rill et al., Mesopontine neuronsin schizophrenia, Neuroscience, 66(2):321-335, 1995). However, theseresults were not confirmed in one study (German et al., Mesopontinecholinergic and non-cholinergic neurons in schizophrenia, Neuroscience,94(1):33-38, 1999).

[0015] Mania

[0016] Mania is a sustained form of euphoria that affects millions ofpeople in the United States who suffer from depression. Manic episodesmay be characterized by an elevated, expansive, or irritable moodlasting several days, and is often accompanied by other symptoms, suchas, overactivity, overtalkativeness, social intrusiveness, increasedenergy, pressure of ideas, grandiosity, distractibility, decreased needfor sleep, and recklessness. Manic patients may also experiencedelusions and hallucinations.

[0017] Depressive disorders may involve serotonergic and noradrenergicneuronal systems based on current therapeutic regimes that targetserotonin and noradrenalin receptors. Serotonergic pathways originatefrom the raphe nuclei of the brain stem, and noradrenergic pathwaysoriginate from the locus ceruleus. Decreasing the electrical activity ofneurons in the locus ceruleus may be associated with the effectsmediated by depression medications.

[0018] Mania likely results from an imbalance in the chemical messengerswithin the brain. It has been proposed that mania may be attributed to adecline in acetylcholine. A decline in acetylcholine may result in arelatively greater level of norepinephrine. Administering phosphotidylcholine has been reported to alleviate the symptoms of mania.

[0019] Anxiety

[0020] Anxiety disorders may affect between approximately ten to thirtypercent of the population, and may be characterized by frequentoccurrence of symptoms of fear including arousal, restlessness,heightened responsiveness, sweating, racing heart, increased bloodpressure, dry mouth, a desire to run or escape, and avoidance behavior.Generalized anxiety persists for several months, and is associated withmotor tension (trembling, twitching, muscle aches, restlessness);autonomic hyperactivity (shortness of breath, palpitations, increasedheart rate, sweating, cold hands), and vigilance and scanning (feelingon edge, exaggerated startle response, difficult in concentrating).

[0021] Benzodiazepines, which enhance the inhibitory effects of thegamma aminobutyric acid (GABA) type A receptor, are frequently used totreat anxiety. Buspirone is another effective anxiety treatment.

[0022] Alzheimer's disease

[0023] Alzheimer's disease is a degenerative brain disordercharacterized by cognitive and noncognitive neuropsychiatric symptoms,which accounts for approximately 60% of all cases of dementia forpatients over 65 years old. Psychiatric symptoms are common inAlzheimer's disease, with psychosis (hallucinations and delusions)present in approximately fifty percent of affected patients. Similar toschizophrenia, positive psychotic symptoms are common in Alzheimer'sdisease. Delusions typically occur more frequently than hallucinations.Alzheimer's patients may also exhibit negative symptoms, such asdisengagement, apathy, diminished emotional responsiveness, loss ofvolition, and decreased initiative.

[0024] Alzheimer's disease patients may also exhibit enlargement of bothlateral and third ventricles as well as atrophy of temporal structures.

[0025] It is possible that the psychotic symptoms of Alzheimer's diseasemay involve a shift in the concentration of dopamine or acetylcholine,which may augment a dopaminergic/cholinergic balance, thereby resultingin psychotic behavior. For example, it has been proposed that anincreased dopamine release may be responsible for the positive symptomsof schizophrenia. This may result in a positive disruption of thedopaminergic/cholinergic balance. In Alzheimer's disease, the reductionin cholinergic neurons effectively reduces acetylcholine releaseresulting in a negative disruption of the dopaminergic/cholinergicbalance. Indeed, antipsychotic agents that are used to relieve psychosisof schizophrenia are also useful in alleviating psychosis in Alzheimer'spatients.

[0026] Several of the symptoms associated with the neuropsychiatricdisorders appear to be, at least in part, attributed tohyperexcitability of neurons within the brain. This interpretation issupported by the pharmacology associated with current therapeutictreatments. For example, many of the antipsychotic treatments aredirected to interfering with binding of dopamine to dopamine receptors,as discussed above. Similarly, mania and anxiety are often treated withbenzodiazepines, which enhance the inhibitory effects of GABA-mediatedinhibition. U.S. Pat. No. 6,306,403 discloses intracranialadministration of a botulinum toxin to treat various movement disorders.Additionally, it is known that stereotactic procedures can be used toadminister a pharmaceutical to a discrete brain area to successfullyalleviate a parkinsonian tremor. See e.g. Pahapill P.A., et al., Tremorarrest with thalamic microinjections of muscimol in patients withessential tremor, Ann Neur 46(2); 249-252 (1999).

[0027] However, current therapeutic treatments result in several adverseside-effects. These side-effects may be attributed to the fact that thepharmaceutical agents are typically administered systemically, andtherefore, the agents have a relatively non-specific action with respectto the various biological systems of the patient. For example,administration of benzodiazepines may result in sedation and musclerelaxation. In addition, tolerance may develop to these drugs, as wellas withdrawal seizures may develop. Current therapeutic strategies alsorequire consistent and repeated administration of the agents to achievethe desired effects.

[0028] Botulinum Toxin

[0029] The genus Clostridium has more than one hundred and twenty sevenspecies, grouped according to their morphology and functions. Theanaerobic, gram positive bacterium Clostridium botulinum produces apotent polypeptide neurotoxin, botulinum toxin, which causes aneuroparalytic illness in humans and animals referred to as botulism.The spores of Clostridium botulinum are found in soil and can grow inimproperly sterilized and sealed food containers of home basedcanneries, which are the cause of many of the cases of botulism. Theeffects of botulism typically appear 18 to 36 hours after eating thefoodstuffs infected with a Clostridium botulinum culture or spores. Thebotulinum toxin can apparently pass unattenuated through the lining ofthe gut and attack peripheral motor neurons. Symptoms of botulinum toxinintoxication can progress from difficulty walking, swallowing, andspeaking to paralysis of the respiratory muscles and death.

[0030] Botulinum toxin type A is the most lethal natural biologicalagent known to man. About 50 picograms of a commercially availablebotulinum toxin type A (purified neurotoxin complex)¹ is a LD₅₀ in mice(i.e. 1 unit). One unit of BOTOX® contains about 50 picograms (about 56attomoles) of botulinum toxin type A complex. Interestingly, on a molarbasis, botulinum toxin type A is about 1.8 billion times more lethalthan diphtheria, about 600 million times more lethal than sodiumcyanide, about 30 million times more lethal than cobra toxin and about12 million times more lethal than cholera. Singh, Critical Aspects ofBacterial Protein Toxins, pages 63-84 (chapter 4) of Natural Toxins II,edited by B. R. Singh et al., Plenum Press, New York (1976) (where thestated LD₅₀ of botulinum toxin type A of 0.3 ng equals 1 U is correctedfor the fact that about 0.05 ng of BOTOX® equals 1 unit). One unit (U)of botulinum toxin is defined as the LD₅₀ upon intraperitoneal injectioninto female Swiss Webster mice weighing 18 to 20 grams each.

[0031] Seven immunologically distinct botulinum neurotoxins have beencharacterized, these being respectively botulinum neurotoxin serotypesA, B, C₁, D, E, F and G each of which is distinguished by neutralizationwith type-specific antibodies. The different serotypes of botulinumtoxin vary in the animal species that they affect and in the severityand duration of the paralysis they evoke. For example, it has beendetermined that botulinum toxin type A is 500 times more potent, asmeasured by the rate of paralysis produced in the rat, than is botulinumtoxin type B. Additionally, botulinum toxin type B has been determinedto be non-toxic in primates at a dose of 480 U/kg which is about 12times the primate LD₅₀ for botulinum toxin type A. Moyer E et al.,Botulinum Toxin Type B: Experimental and Clinical Experience, beingchapter 6, pages 71-85 of “Therapy With Botulinum Toxin”, edited byJankovic, J. et al. (1994), Marcel Dekker, Inc. Botulinum toxinapparently binds with high affinity to cholinergic motor neurons, istranslocated into the neuron and blocks the release of acetylcholine.

[0032] Regardless of serotype, the molecular mechanism of toxinintoxication appears to be similar and to involve at least three stepsor stages. In the first step of the process, the toxin binds to thepresynaptic membrane of the target neuron through a specific interactionbetween the heavy chain, H chain, and a cell surface receptor; thereceptor is thought to be different for each type of botulinum toxin andfor tetanus toxin. The carboxyl end segment of the H chain, H_(C),appears to be important for targeting of the toxin to the cell surface.

[0033] In the second step, the toxin crosses the plasma membrane of thepoisoned cell. The toxin is first engulfed by the cell throughreceptor-mediated endocytosis, and an endosome containing the toxin isformed. The toxin then escapes the endosome into the cytoplasm of thecell. This step is thought to be mediated by the amino end segment ofthe H chain, H_(N), which triggers a conformational change of the toxinin response to a pH of about 5.5 or lower. Endosomes are known topossess a proton pump which decreases intra-endosomal pH. Theconformational shift exposes hydrophobic residues in the toxin, whichpermits the toxin to embed itself in the endosomal membrane. The toxin(or at a minimum the light chain) then translocates through theendosomal membrane into the cytoplasm.

[0034] The last step of the mechanism of botulinum toxin activityappears to involve reduction of the disulfide bond joining the heavychain, H chain, and the light chain, L chain. The entire toxic activityof botulinum and tetanus toxins is contained in the L chain of theholotoxin; the L chain is a zinc (Zn++) endopeptidase which selectivelycleaves proteins essential for recognition and docking ofneurotransmitter-containing vesicles with the cytoplasmic surface of theplasma membrane, and fusion of the vesicles with the plasma membrane.Tetanus neurotoxin, botulinum toxin types B, D, F, and G causedegradation of synaptobrevin (also called vesicle-associated membraneprotein (VAMP)), a synaptosomal membrane protein. Most of the VAMPpresent at the cytoplasmic surface of the synaptic vesicle is removed asa result of any one of these cleavage events. Botulinum toxin serotype Aand E cleave SNAP-25. Botulinum toxin serotype C₁ was originally thoughtto cleave syntaxin, but was found to cleave syntaxin and SNAP-25. Eachof the botulinum toxins specifically cleaves a different bond, exceptbotulinum toxin type B (and tetanus toxin) which cleave the same bond.

[0035] Botulinum toxins have been used in clinical settings for thetreatment of neuromuscular disorders characterized by hyperactiveskeletal muscles. A botulinum toxin type A complex has been approved bythe U.S. Food and Drug Administration for the treatment ofblepharospasm, strabismus and hemifacial spasm. Non-type A botulinumtoxin serotypes apparently have a lower potency and/or a shorterduration of activity as compared to botulinum toxin type A. Clinicaleffects of peripheral intramuscular botulinum toxin type A are usuallyseen within one week of injection. The typical duration of symptomaticrelief from a single intramuscular injection of botulinum toxin type Aaverages about three months.

[0036] Although all the botulinum toxins serotypes apparently inhibitrelease of the neurotransmitter acetylcholine at the neuromuscularjunction, they do so by affecting different neurosecretory proteinsand/or cleaving these proteins at different sites. For example,botulinum types A and E both cleave the 25 kiloDalton (kD) synaptosomalassociated protein (SNAP-25), but they target different amino acidsequences within this protein. Botulinum toxin types B, D, F and G acton vesicle-associated protein (VAMP, also called synaptobrevin), witheach serotype cleaving the protein at a different site. Finally,botulinum toxin type C₁ has been shown to cleave both syntaxin andSNAP-25. These differences in mechanism of action may affect therelative potency and/or duration of action of the various botulinumtoxin serotypes. Apparently, a substrate for a botulinum toxin can befound in a variety of different cell types. See e.g. Biochem, J 1;339(pt 1):159-65:1999, and Mov Disord, 10(3):376:1995 (pancreatic islet Bcells contains at least SNAP-25 and synaptobrevin).

[0037] The molecular weight of the botulinum toxin protein molecule, forall seven of the known botulinum toxin serotypes, is about 150 kD.Interestingly, the botulinum toxins are released by Clostridialbacterium as complexes comprising the 150 kD botulinum toxin proteinmolecule along with associated non-toxin proteins. Thus, the botulinumtoxin type A complex can be produced by Clostridial bacterium as 900 kD,500 kD and 300 kD forms. Botulinum toxin types B and C₁ is apparentlyproduced as only a 700 kD or 500 kD complex. Botulinum toxin type D isproduced as both 300 kD and 500 kD complexes. Finally, botulinum toxintypes E and F are produced as only approximately 300 kD complexes. Thecomplexes (i.e. molecular weight greater than about 150 kD) are believedto contain a non-toxin hemaglutinin protein and a non-toxin andnon-toxic nonhemaglutinin protein. These two non-toxin proteins (whichalong with the botulinum toxin molecule comprise the relevant neurotoxincomplex) may act to provide stability against denaturation to thebotulinum toxin molecule and protection against digestive acids whentoxin is ingested. Additionally, it is possible that the larger (greaterthan about 150 kD molecular weight) botulinum toxin complexes may resultin a slower rate of diffusion of the botulinum toxin away from a site ofintramuscular injection of a botulinum toxin complex.

[0038] In vitro studies have indicated that botulinum toxin inhibitspotassium cation induced release of both acetylcholine andnorepinephrine from primary cell cultures of brainstem tissue.Additionally, it has been reported that botulinum toxin inhibits theevoked release of both glycine and glutamate in primary cultures ofspinal cord neurons and that in brain synaptosome preparations botulinumtoxin inhibits the release of each of the neurotransmittersacetylcholine, dopamine, norepinephrine (Habermann E., et al., TetanusToxin and Botulinum A and C Neurotoxins Inhibit Noradrenaline ReleaseFrom Cultured Mouse Brain, J Neurochem 51(2);522-527:1988) CGRP,substance P and glutamate (Sanchez-Prieto, J., et al., Botulinum Toxin ABlocks Glutamate Exocytosis From Guinea Pig Cerebral CorticalSynaptosomes, Eur J. Biochem 165;675-681:1897. Thus, when adequateconcentrations are used, stimulus-evoked release of mostneurotransmitters is blocked by botulinum toxin. See e.g. Pearce, L. B.,Pharmacologic Characterization of Botulinum Toxin For Basic Science andMedicine, Toxicon 35(9);1373-1412 at 1393; Bigalke H., et al., BotulinumA Neurotoxin Inhibits Non-Cholinergic Synaptic Transmission in MouseSpinal Cord Neurons in Culture, Brain Research 360;318-324:1985;Habermann E., Inhibition by Tetanus and Botulinum A Toxin of the releaseof [ ³ H]Noradrenaline and [ ³ H]GABA From Rat Brain Homogenate,Experientia 44;224-226:1988, Bigalke H., et al., Tetanus Toxin andBotulinum A Toxin Inhibit Release and Uptake of Various Transmitters, asStudied with Particulate Preparations From Rat Brain and Spinal Cord,Naunyn-Schmiedeberg's Arch Pharmacol 316;244-251:1981, and; Jankovic J.et al., Therapy With Botulinum Toxin, Marcel Dekker, Inc., (1994), page5.

[0039] Botulinum toxin type A can be obtained by establishing andgrowing cultures of Clostridium botulinum in a fermenter and thenharvesting and purifying the fermented mixture in accordance with knownprocedures. All the botulinum toxin serotypes are initially synthesizedas inactive single chain proteins which must be cleaved or nicked byproteases to become neuroactive. The bacterial strains that makebotulinum toxin serotypes A and G possess endogenous proteases andserotypes A and G can therefore be recovered from bacterial cultures inpredominantly their active form. In contrast, botulinum toxin serotypesC₁, D and E are synthesized by nonproteolytic strains and are thereforetypically unactivated when recovered from culture. Serotypes B and F areproduced by both proteolytic and nonproteolytic strains and thereforecan be recovered in either the active or inactive form. However, eventhe proteolytic strains that produce, for example, the botulinum toxintype B serotype only cleave a portion of the toxin produced. The exactproportion of nicked to unnicked molecules depends on the length ofincubation and the temperature of the culture. Therefore, a certainpercentage of any preparation of, for example, the botulinum toxin typeB toxin is likely to be inactive, possibly accounting for the knownsignificantly lower potency of botulinum toxin type B as compared tobotulinum toxin type A. The presence of inactive botulinum toxinmolecules in a clinical preparation will contribute to the overallprotein load of the preparation, which has been linked to increasedantigenicity, without contributing to its clinical efficacy.Additionally, it is known that botulinum toxin type B has, uponintramuscular injection, a shorter duration of activity and is also lesspotent than botulinum toxin type A at the same dose level.

[0040] High quality crystalline botulinum toxin type A can be producedfrom the Hall A strain of Clostridium botulinum with characteristics of>3×10⁷ U/mg, an A₂₆₀/A₂₇₈ of less than 0.60 and a distinct pattern ofbanding on gel electrophoresis. The known Shantz process can be used toobtain crystalline botulinum toxin type A, as set forth in Shantz, E.J., et al, Properties and use of Botulinum toxin and Other MicrobialNeurotoxins in Medicine, Microbiol Rev. 56;80-99:1992. Generally, thebotulinum toxin type A complex can be isolated and purified from ananaerobic fermentation by cultivating Clostridium botulinum type A in asuitable medium. The known process can also be used, upon separation outof the non-toxin proteins, to obtain pure botulinum toxins, such as forexample: purified botulinum toxin type A with an approximately 150 kDmolecular weight with a specific potency of 1-2×10⁸ LD₅₀ U/mg orgreater; purified botulinum toxin type B with an approximately 156 kDmolecular weight with a specific potency of 1-2×10⁸ LD₅₀ U/mg orgreater, and; purified botulinum toxin type F with an approximately 155kD molecular weight with a specific potency of 1-2×10⁷ LD₅₀ U/mg orgreater.

[0041] Botulinum toxins and/or botulinum toxin complexes can be obtainedfrom List Biological Laboratories, Inc., Campbell, California; theCentre for Applied Microbiology and Research, Porton Down, U.K.; Wako(Osaka, Japan), Metabiologics (Madison, Wis.) as well as from SigmaChemicals of St Louis, Mo.

[0042] Pure botulinum toxin is so labile that it is generally not usedto prepare a pharmaceutical composition. Furthermore, the botulinumtoxin complexes, such as the toxin type A complex are also extremelysusceptible to denaturation due to surface denaturation, heat, andalkaline conditions. Inactivated toxin forms toxoid proteins which maybe immunogenic. The resulting antibodies can render a patient refractoryto toxin injection.

[0043] As with enzymes generally, the biological activities of thebotulinum toxins (which are intracellular peptidases) is dependant, atleast in part, upon their three dimensional conformation. Thus,botulinum toxin type A is detoxified by heat, various chemicals surfacestretching and surface drying. Additionally, it is known that dilutionof the toxin complex obtained by the known culturing, fermentation andpurification to the much, much lower toxin concentrations used forpharmaceutical composition formulation results in rapid detoxificationof the toxin unless a suitable stabilizing agent is present. Dilution ofthe toxin from milligram quantities to a solution containing nanogramsper milliliter presents significant difficulties because of the rapidloss of specific toxicity upon such great dilution. Since the toxin maybe used months or years after the toxin containing pharmaceuticalcomposition is formulated, the toxin can stabilized with a stabilizingagent such as albumin and gelatin.

[0044] A commercially available botulinum toxin containingpharmaceutical composition is sold under the trademark BOTOX® (availablefrom Allergan, Inc., of Irvine, Calif.). BOTOX® consists of a purifiedbotulinum toxin type A complex, albumin and sodium chloride packaged insterile, vacuum-dried form. The botulinum toxin type A is made from aculture of the Hall strain of Clostridium botulinum grown in a mediumcontaining N-Z amine and yeast extract. The botulinum toxin type Acomplex is purified from the culture solution by a series of acidprecipitations to a crystalline complex consisting of the active highmolecular weight toxin protein and an associated hemagglutinin protein.The crystalline complex is re-dissolved in a solution containing salineand albumin and sterile filtered (0.2 microns) prior to vacuum-drying.The vacuum-dried product is stored in a freezer at or below −5° C.BOTOX® can be reconstituted with sterile, non-preserved saline prior tointramuscular injection. Each vial of BOTOX® contains about 100 units(U) of Clostridium botulinum toxin type A purified neurotoxin complex,0.5 milligrams of human serum albumin and 0.9 milligrams of sodiumchloride in a sterile, vacuum-dried form without a preservative.

[0045] To reconstitute vacuum-dried BOTOX®, sterile normal salinewithout a preservative; (0.9% Sodium Chloride Injection) is used bydrawing up the proper amount of diluent in the appropriate size syringe.Since BOTOX® may be denatured by bubbling or similar violent agitation,the diluent is gently injected into the vial. For sterility reasonsBOTOX® is preferably administered within four hours after the vial isremoved from the freezer and reconstituted. During these four hours,reconstituted BOTOX® can be stored in a refrigerator at about 2° C. toabout 8° C. Reconstituted, refrigerated BOTOX® has been reported toretain its potency for at least about two weeks. Neurology,48:249-53:1997.

[0046] It has been reported that botulinum toxin type A has been used inclinical settings as follows:

[0047] (1) about 75-125 units of BOTOX® per intramuscular injection(multiple muscles) to treat cervical dystonia;

[0048] (2) 5-10 units of BOTOX® per intramuscular injection to treatglabellar lines (brow furrows) (5 units injected intramuscularly intothe procerus muscle and 10 units injected intramuscularly into eachcorrugator supercilii muscle);

[0049] (3) about 30-80 units of BOTOX® to treat constipation byintrasphincter injection of the puborectalis muscle;

[0050] (4) about 1-5 units per muscle of intramuscularly injected BOTOX®to treat blepharospasm by injecting the lateral pre-tarsal orbicularisoculi muscle of the upper lid and the lateral pre-tarsal orbicularisoculi of the lower lid.

[0051] (5) to treat strabismus, extraocular muscles have been injectedintramuscularly with between about 1-5 units of BOTOX®, the amountinjected varying based upon both the size of the muscle to be injectedand the extent of muscle paralysis desired (i.e. amount of dioptercorrection desired).

[0052] (6) to treat upper limb spasticity following stroke byintramuscular injections of BOTOX® into five different upper limb flexormuscles, as follows:

[0053] (a) flexor digitorum profundus: 7.5 U to 30 U

[0054] (b) flexor digitorum sublimus: 7.5 U to 30 U

[0055] (c) flexor carpi ulnaris: 10 U to 40 U

[0056] (d) flexor carpi radialis: 15 U to 60 U

[0057] (e) biceps brachii: 50 U to 200 U. Each of the five indicatedmuscles has been injected at the same treatment session, so that thepatient receives from 90 U to 360 U of upper limb flexor muscle BOTOX®by intramuscular injection at each treatment session.

[0058] (7) to treat migraine, pericranial injected (injectedsymmetrically into glabellar, frontalis and temporalis muscles)injection of 25 U of BOTOX® has showed significant benefit as aprophylactic treatment of migraine compared to vehicle as measured bydecreased measures of migraine frequency, maximal severity, associatedvomiting and acute medication use over the three month period followingthe 25 U injection.

[0059] Additionally, intramuscular botulinum toxin has been used in thetreatment of tremor in patients with Parkinson's disease, although ithas been reported that results have not been impressive. Marjama-Jyons,J., et al., Tremor-Predominant Parkinson's Disease, Drugs & Aging16(4);273-278:2000.

[0060] It is known that botulinum toxin type A can have an efficacy forup to 12 months (European J. Neurology 6 (Supp 4): S11-S1150:1999), andin some circumstances for as long as 27 months. The Laryngoscope109:1344-1346:1999. However, the usual duration of an intramuscularinjection of Botox® is typically about 3 to 4 months.

[0061] The success of botulinum toxin type A to treat a variety ofclinical conditions has led to interest in other botulinum toxinserotypes. Two commercially available botulinum type A preparations foruse in humans are BOTOX® available from Allergan, Inc., of Irvine,Calif., and Dysport® available from Beaufour Ipsen, Porton Down,England. A Botulinum toxin type B preparation (MyoBloc®) is availablefrom Elan Pharmaceuticals of San Francisco, Calif.

[0062] In addition to having pharmacologic actions at the peripherallocation, botulinum toxins may also have inhibitory effects in thecentral nervous system. Work by Weigand et al, Nauny-Schmiedeberg'sArch. Pharmacol. 1976; 292,161-165, and Habermann, Nauny-Schmiedeberg'sArch. Pharmacol. 1974; 281, 47-56 showed that botulinum toxin is able toascend to the spinal area by retrograde transport. As such, a botulinumtoxin injected at a peripheral location, for example intramuscularly,may be retrograde transported to the spinal cord.

[0063] U.S. Pat. No. 5,989,545 discloses that a modified clostridialneurotoxin or fragment thereof, preferably a botulinum toxin, chemicallyconjugated or recombinantly fused to a particular targeting moiety canbe used to treat pain by administration of the agent to the spinal cord.

[0064] Acetylcholine

[0065] Typically only a single type of small molecule neurotransmitteris released by each type of neuron in the mammalian nervous system. Theneurotransmitter acetylcholine is secreted by neurons in many areas ofthe brain, but specifically by the large pyramidal cells of the motorcortex, by several different neurons in the basal ganglia, by the motorneurons that innervate the skeletal muscles, by the preganglionicneurons of the autonomic nervous system (both sympathetic andparasympathetic), by the postganglionic neurons of the parasympatheticnervous system, and by some of the postganglionic neurons of thesympathetic nervous system. Essentially, only the postganglionicsympathetic nerve fibers to the sweat glands, the piloerector musclesand a few blood vessels are cholinergic as most of the postganglionicneurons of the sympathetic nervous system secret the neurotransmitternorepinephine. In most instances acetylcholine has an excitatory effect.However, acetylcholine is known to have inhibitory effects at some ofthe peripheral parasympathetic nerve endings, such as inhibition ofheart rate by the vagal nerve.

[0066] The efferent signals of the autonomic nervous system aretransmitted to the body through either the sympathetic nervous system orthe parasympathetic nervous system. The preganglionic neurons of thesympathetic nervous system extend from preganglionic sympathetic neuroncell bodies located in the intermediolateral horn of the spinal cord.The preganglionic sympathetic nerve fibers, extending from the cellbody, synapse with postganglionic neurons located in either aparavertebral sympathetic ganglion or in a prevertebral ganglion. Since,the preganglionic neurons of both the sympathetic and parasympatheticnervous system are cholinergic, application of acetylcholine to theganglia will excite both sympathetic and parasympathetic postganglionicneurons.

[0067] Acetylcholine activates two types of receptors, muscarinic andnicotinic receptors. The muscarinic receptors are found in all effectorcells stimulated by the postganglionic, neurons of the parasympatheticnervous system as well as in those stimulated by the postganglioniccholinergic neurons of the sympathetic nervous system. The nicotinicreceptors are found in the adrenal medulla, as well as within theautonomic ganglia, that is on the cell surface of the postganglionicneuron at the synapse between the preganglionic and postganglionicneurons of both the sympathetic and parasympathetic systems. Nicotinicreceptors are also found in many nonautonomic nerve endings, for examplein the membranes of skeletal muscle fibers at the neuromuscularjunction.

[0068] Acetylcholine is released from cholinergic neurons when small,clear, intracellular vesicles fuse with the presynaptic neuronal cellmembrane. A wide variety of non-neuronal secretory cells, such as,adrenal medulla (as well as the PC12 cell line) and pancreatic isletcells release catecholamines and parathyroid hormone, respectively, fromlarge dense-core vesicles. The PC12 cell line is a clone of ratpheochromocytoma cells extensively used as a tissue culture model forstudies of sympathoadrenal development. Botulinum toxin inhibits therelease of both types of compounds from both types of cells in vitro,permeabilized (as by electroporation) or by direct injection of thetoxin into the denervated cell. Botulinum toxin is also known to blockrelease of the neurotransmitter glutamate from cortical synaptosomescell cultures.

[0069] A neuromuscular junction is formed in skeletal muscle by theproximity of axons to muscle cells. A signal transmitted through thenervous system results in an action potential at the terminal axon, withactivation of ion channels and resulting release of the neurotransmitteracetylcholine from intraneuronal synaptic vesicles, for example at themotor endplate of the neuromuscular junction. The acetylcholine crossesthe extracellular space to bind with acetylcholine receptor proteins onthe surface of the muscle end plate. Once sufficient binding hasoccurred, an action potential of the muscle cell causes specificmembrane ion channel changes, resulting in muscle cell contraction. Theacetylcholine is then released from the muscle cells and metabolized bycholinesterases in the extracellular space. The metabolites are recycledback into the terminal axon for reprocessing into further acetylcholine.

[0070] What is needed therefore is a method for effectively treating aneuropsychiatric disorder by administration of a pharmaceutical whichhas the characteristics of long duration of activity, low rates ofdiffusion out of a chosen intracranial target tissue where administered,and nominal systemic effects at therapeutic dose levels.

SUMMARY

[0071] The present invention meets this need and provides methods foreffectively treating neuropsychiatric disorders by intracranialadministration of a neurotoxin which has the characteristics of longduration of activity, low rates of diffusion out of an intracranial sitewhere administered and insignificant systemic effects at therapeuticdose levels.

[0072] The following definitions apply herein:

[0073] “About” means approximately or nearly and in the context of anumerical value or range set forth herein means ±10% of the numericalvalue or range recited or claimed.

[0074] “Local administration” means direct administration of apharmaceutical at or to the vicinity of a site on or within an animalbody, at which site a biological effect of the pharmaceutical isdesired. Local administration excludes systemic routes ofadministration, such as intravenous or oral administration.

[0075] “Neurotoxin” means a biologically active molecule with a specificaffinity for a neuronal cell surface receptor. Neurotoxin includesClostridial toxins both as pure toxin and as complexed with one to morenon-toxin, toxin associated proteins

[0076] “Intracranial” means within the cranium or at or near the dorsalend of the spinal cord and includes the medulla, brain stem, pons,cerebellum and cerebrum.

[0077] Methods for treating neuropsychiatric disorders comprise the stepof intracranially administering a neurotoxin to a patient. Theneurotoxin is administered in a therapeutically effective amount toalleviate at least one symptom of the disorder. The neurotoxinalleviates the symptoms associated with the disorder by reducingsecretions of neurotransmitter from the neurons exposed to theneurotoxin.

[0078] A suitable neurotoxin may be a neurotoxin made by a bacterium,for example, the neurotoxin may be made from a Clostridium botulinum,Clostridium butyricum, or Clostridium beratti. In certain embodiments ofthe invention, neuropsychiatric disorders are treated by intracraniallyadministering a botulinum toxin to the patient. The botulinum toxin maybe a botulinum toxin type A, type B, type C₁, type D, type E, type F, ortype G. The botulinum toxin may be administered in an amount of betweenabout 10⁻³ U/kg and about 10 U/kg. The effects of the botulinum toxinmay persist for between about 1 month and 5 years.

[0079] Other neurotoxins include recombinantly produced neurotoxins,such as botulinum toxins produced by E. coli. In addition oralternatively, the neurotoxin can be a modified neurotoxin, that is aneurotoxin which has at least one of its amino acids deleted, modifiedor replaced, as compared to a native or the modified neurotoxin can be arecombinant produced neurotoxin or a derivative or fragment thereof. Theneurotoxins are still able to inhibit neurotransmitter release.

[0080] The neurotoxin is administered to a site within the brain that isbelieved to be involved in the disorder being treated. The neurotoxinmay be administered to a lower brain region, the pontine region, thepedunculopontine nucleus, the locus ceruleus, or the ventral tegmentalarea, for example. The neurotoxin may alleviate the symptom that isassociated with hyperactive neurotransmitter release. The neurotoxin mayalso restore a balance between two neuronal systems to alleviate thedisorder. The neurotoxin administered to the patient may inhibitacetylcholine release from cholinergic neurons, may inhibit dopaminerelease from dopaminergic neurons, may inhibit the release ofnorepinephrine from noradrenergic neurons.

[0081] The neuropsychiatric disorders treated in accordance with themethods disclosed herein include, and are not limited to, schizophrenia,Alzheimer's disease, mania, and anxiety. The neurotoxin can alleviate apositive symptom associated with the neuropsychiatric disorder, forexample schizophrenia, and can alleviate the symptoms within a few hoursafter administration.

[0082] I have surprisingly found that a botulinum toxin, such asbotulinum toxin type A, can be intracranially administered in amountsbetween about 10⁻⁴ U/kg and about 10 U/kg to alleviate aneuropsychiatric disorder experienced by a human patient. Preferably,the botulinum toxin used is intracranially administered in an amount ofbetween about 10⁻³ U/kg and about 1 U/kg. Most preferably, the botulinumtoxin is administered in an amount of between about 0.1 unit and about 5units. Significantly, the neuropsychiatric disorder alleviating effectof the present disclosed methods can persist for between about 2 monthsto about 6 months when administration is of aqueous solution of theneurotoxin, and for up to about five years when the neurotoxin isadministered as a controlled release implant.

[0083] Another preferred method within the scope of the presentinvention is a method for improving patient function, the methodcomprising the step of intracranially administering a neurotoxin to a 20patient, thereby improving patient function as determined by improvementin one or more of the factors of reduced pain, reduced time spent inbed, increased ambulation, healthier attitude and a more variedlifestyle.

DESCRIPTION

[0084] The present invention is based on the discovery that intracranialadministration of a neurotoxin can provide significant and long lastingrelief from a variety of different neuropsychiatric disorders.Intracranial administration permits a neurotoxin to be locallyadministered at a site, within a patient's cranium, that has a directeffect on the neurons involved in the disorders, and avoidscomplications associated with passage of the neurotoxin across the bloodbrain barrier. Thus, intracranial administration provides greater localdosages of a neurotoxin to a brain area than is achieved with systemicroutes of administration, and avoids the non-specificity associated withsystemic administration of current therapeutic agents. Indeed, systemicadministration of a neurotoxin, such as a botulinum toxin, iscontraindicated due to the severe complications (i.e. botulism) whichcan result from entry of a botulinum toxin into the patient's generalcirculation.

[0085] The neurotoxins used in accordance with the invention disclosedherein are neurotoxins that inhibit transmission of chemical orelectrical signals between select neuronal groups that are involved inthe neuropsychiatric disorders. The neurotoxins preferably are notcytotoxic to the cells that are exposed to the neurotoxin. Theneurotoxin may inhibit neurotransmission by reducing or preventingexocytosis of neurotransmitter from the neurons exposed to theneurotoxin. Or, neurotoxins may reduce neurotransmission by inhibitingthe generation of action potentials of the neurons exposed to the toxin.The suppressive effects provided by the neurotoxin should persist for arelatively long period of time, for example, for more than two months,and potentially for several years.

[0086] Examples of neurotoxins used to treat neuropsychiatric disorders,include, and are not limited to, neurotoxins made from Clostridiumbacteria, such as Clostridium botulinum, Clostridium butyricum andClostridium beratti. In addition, the neurotoxins used in the methods ofthe invention may be a botulinum toxin selected from a group ofbotulinum toxin types A, B, C, D, E, F, and G. In one embodiment of theinvention, the neurotoxin administered to the patient is botulinum toxintype A. Botulinum toxin type A is desirable due to its high potency inhumans, ready availability, and known use for the treatment of skeletaland smooth muscle disorders when locally administered by intramuscularinjection. The present invention also includes the use of (a)neurotoxins obtained or processed by bacterial culturing, toxinextraction, concentration, preservation, freeze drying, and/orreconstitution; and/or (b) modified or recombinant neurotoxins, that isneurotoxins that have had one or more amino acids or amino acidsequences deliberately deleted, modified or replaced by knownchemical/biochemical amino acid modification procedures or by use ofknown host cell/recombinant vector recombinant technologies, as well asderivatives or fragments of neurotoxins so made. These neurotoxinvariants should retain the ability to inhibit neurotransmission betweenor among neurons, and some of these variants may provide increaseddurations of inhibitory effects as compared to native neurotoxins, ormay provide enhanced binding specificity to the neurons exposed to theneurotoxins. These neurotoxin variants may be selected by screening thevariants using conventional assays to identify neurotoxins that have thedesired physiological effects of inhibiting neurotransmission.

[0087] Botulinum toxins for use according to the present invention canbe stored in lyophilized, vacuum dried form in containers under vacuumpressure or as stable liquids. Prior to lyophilization the botulinumtoxin can be combined with pharmaceutically acceptable excipients,stabilizers and/or carriers, such as albumin. The lyophilized materialcan be reconstituted with saline or water to create a solution orcomposition containing the botulinum toxin to be administered to thepatient.

[0088] Although the composition may only contain a single type ofneurotoxin, such as botulinum toxin type A, as the active ingredient tosuppress neurotransmission, other therapeutic compositions may includetwo or more types of neurotoxins, which may provide enhanced therapeuticeffects of the disorders. For example, a composition administered to apatient may include botulinum toxin type A and botulinum toxin type B.Administering a single composition containing two different neurotoxinsmay permit the effective concentration of each of the neurotoxins to belower than if a single neurotoxin is administered to the patient whilestill achieving the desired therapeutic effects. The compositionadministered to the patient may also contain other pharmaceuticallyactive ingredients, such as, protein receptor or ion channel modulators,in combination with the neurotoxin or neurotoxins. These modulators maycontribute to the reduction in neurotransmission between the variousneurons. For example, a composition may contain gamma aminobutyric acid(GABA) type A receptor modulators that enhance the inhibitory effectsmediated by the GABA_(A) receptor. The GABA_(A) receptor inhibitsneuronal activity by effectively shunting current flow across the cellmembrane. GABA_(A) receptor modulators may enhance the inhibitoryeffects of the GABA_(A) receptor and reduce electrical or chemicalsignal transmission from the neurons. Examples of GABA_(A) receptormodulators include benzodiazepines, such as diazepam, oxaxepam,lorazepam, prazepam, alprazolam, halazeapam, chordiazepoxide, andchlorazepate. Compositions may also contain glutamate receptormodulators that decrease the excitatory effects mediated by glutamatereceptors. Examples of glutamate receptor modulators include agents thatinhibit current flux through AMPA, NMDA, and/or kainate types ofglutamate receptors. The compositions may also include agents thatmodulate dopamine receptors, such as antipsychotics, norepinephrinereceptors, and/or serotonin receptors. The compositions may also includeagents that affect ion flux through voltage gated calcium channels,potassium channels, and/or sodium channels. Thus, the compositions usedto treat neuropsychiatric disorders may include one or more neurotoxins,such as botulinum toxins, in addition to ion channel receptor modulatorsthat may reduce neurotransmission.

[0089] The neurotoxin may be intracranially administered by any suitablemethod as determined by the attending physician. The methods ofadministration permit the neurotoxin to be administered locally to aselected target tissue. Methods of administration include injection of asolution or composition containing the neurotoxin, as described above,and include implantation of a controlled release system thatcontrollably releases the neurotoxin to the target tissue. Suchcontrolled release systems reduce the need for repeat injections.Diffusion of biological activity of a botulinum toxin within a tissueappears to be a function of dose and can be graduated. Jankovic J., etal Therapy With Botulinum Toxin, Marcel Dekker, Inc., (1994), page 150.Thus, diffusion of botulinum toxin can be controlled to reducepotentially undesirable side effects that may affect the patient'scognitive abilities. For example, the neurotoxin may be administered sothat the neurotoxin primarily effects neural systems believed to beinvolved in the neuropsychiatric disorder, and does not have negativelyadverse effects on other neural systems, such as primary sensorysystems.

[0090] In addition, the neurotoxin may be administered to the patient inconjunction with a solution or composition that locally decreases the pHof the target tissue environment. For example, a solution containinghydrochloric acid may be used to locally and temporarily reduce the pHof the target tissue environment to facilitate translocation of theneurotoxin across cell membranes. The reduction in local pH may bedesirable when the composition contains fragments of neurotoxins thatmay not have a functional targeting moiety (e.g., a portion of the toxinthat binds to a neurotoxin receptor), and/or a translocation domain). Byway of example, and not by way of limitation, a fragment of a botulinumtoxin that comprises the proteolytic domain of the toxin may beadministered to the patient in conjunction with an agent that decreasesthe local pH of the target tissue. Without wishing to be bound by anyparticular theory, it is believed that the lower pH may facilitate thetranslocation of the proteolytic domain across the cell membrane so thatthe neurotoxin fragment can exert its toxic effects within the cell. ThepH of the target tissue is only temporarily lowered so that neuronaland/or glial injury is reduced.

[0091] Similarly, the neurotoxin may be administered intracranially, anda composition containing other pharmaceutical agents, such asantipsychotics, that can cross the blood brain barrier may beadministered systemically, such as by intravenous administration, toachieve the desired therapeutic effects.

[0092] The neurotoxin may also be administered intracranially usingintracranial implants. Intracranial implants have been used for variousconditions. For example, stereotactically implanted, temporary,iodine-125 interstitial catheters can be used to treat malignantgliomas. Scharfen, C.O., et al., High Activity Iodine-125 InterstitialImplant For Gliomas, Int. J. Radiation Oncology Biol Phys24(4);583-591:1992. Additionally, permanent, intracranial, low dose ¹²⁵Iseeded catheter implants have been used to treat brain tumors. Gaspar,et al., Permanent ¹²⁵ I Implants for Recurrent Malignant Gliomas, Int JRadiation Oncology Biol Phys 43(5);977-982:1999. See also chapter 66,pages 577-580, Bellezza D., et al., Stereotactic InterstitialBrachytherapy, in Gildenberg P. L. et al., Textbook of Stereotactic andFunctional Neurosurgery, McGraw-Hill (1998).

[0093] Surgically implanted biodegradable implants have been utilized tolocally administer anti-cancer drugs to treat malignant gliomas. Forexample, polyanhydride wafers containing3-bis(chloro-ethyl)-1-nitrosourea (BCNU) (Carmustine) have been used asintracranial implants. Brem, H. et al., The Safety of InterstitialChemotherapy with BCNU-Loaded Polymer Followed by Radiation Therapy inthe Treatment of Newly Diagnosed Malignant Gliomas: Phase I Trial, JNeuro-Oncology 26:111-123:1995.

[0094] A polyanhydride polymer, Gliadel® (Stolle R & D, Inc.,Cincinnati, Ohio) a copolymer of poly-carboxyphenoxypropane and sebacicacid in a ratio of 20:80 has been used to make implants, and has beenintracranially implanted to treat malignant gliomas. Polymer and BCNUcan be co-dissolved in methylene chloride and spray-dried intomicrospheres. The microspheres can then be pressed into discs 1.4 cm indiameter and 1.0 mm thick by compression molding, packaged in aluminumfoil pouches under nitrogen atmosphere and sterilized by 2.2 megaRads ofgamma irradiation. The polymer permits release of carmustine over a 2-3week period, although it can take more than a year for the polymer to belargely degraded. Brem, H., et al, Placebo-Controlled Trial of Safetyand Efficacy of Intraoperative Controlled Delivery by BiodegradablePolymers of Chemotherapy for Recurrent Gliomas, Lancet 345;1008-1012:1995.

[0095] Implants useful in practicing the methods disclosed herein may beprepared by mixing a desired amount of a stabilized neurotoxin (such asnon-reconstituted BOTOX®) into a solution of a suitable polymerdissolved in methylene chloride. The solution may be prepared at roomtemperature. The solution can then be transferred to a Petri dish andthe methylene chloride evaporated in a vacuum desiccator. Depending uponthe implant size desired and hence the amount of incorporatedneurotoxin, a suitable amount of the dried neurotoxin incorporatingimplant is compressed at about 8000 p.s.i. for 5 seconds or at 3000p.s.i. for 17 seconds in a mold to form implant discs encapsulating theneurotoxin. See e.g. Fung L. K. et al., Pharmacokinetics of InterstitialDelivery of Carmustine 4-Hydroperoxycyclophosphamide and Paclitaxel Froma Biodegradable Polymer Implant in the Monkey Brain, Cancer Research58;672-684:1998.

[0096] Local, intracranial delivery of a neurotoxin, such as a botulinumtoxin, can provide a high, local therapeutic level of the toxin and cansignificantly prevent the occurrence of any systemic toxicity since manyneurotoxins, such as the botulinum toxins, are too large to cross theblood brain barrier. A controlled release polymer capable of long term,local delivery of a neurotoxin to an intracranial site can circumventthe restrictions imposed by systemic toxicity and the blood brainbarrier, and permit effective dosing of an intracranial target tissue. Asuitable implant, as set forth in U.S. Pat. No. 6,306,423 entitled“Neurotoxin Implant”, allows the direct introduction of achemotherapeutic agent to a brain target tissue via a controlled releasepolymer. The implant polymers used are preferably hydrophobic so as toprotect the polymer incorporated neurotoxin from water induceddecomposition until the toxin is released into the target tissueenvironment.

[0097] Local intracranial administration of a botulinum toxin, accordingto the present invention, by injection or implant to a nucleus of thebrain having neurons believed to be involved in symptoms associated withneuropsychiatric disorder provides a superior alternative to systemicadministration of pharmaceuticals to patients to alleviate the symptomsassociated with neuropsychiatric disorders.

[0098] The target sites for administration of the neurotoxin to thepatient may be targeted by using a stereotactic placement apparatus. Forexample, a neurotoxin containing implant, or a needle containing aneurotoxin, may be stereotactically placed at a desired target siteusing the Riechert-Mundinger unit and the ZD (Zamorano-Dujovny)multipurpose localizing unit. A contrast-enhanced computerizedtomography (CT) scan, injecting 120 ml of omnipaque, 350 mg iodine/ml,with 2 mm slice thickness can allow three dimensional multiplanartreatment planning (STP, Fischer, Freiburg, Germany). This equipmentpermits planning on the basis of magnetic resonance imaging studies,merging the CT and MRI target information for clear target confirmation.

[0099] Other stereotactic systems may also be used, including forexample, the Leksell stereotactic system (Downs Surgical, Inc., Decatur,GA) modified for use with a GE CT scanner (General Electric Company,Milwaukee, Wis.) as well as the Brown-Roberts-Wells (BRW) stereotacticsystem (Radionics, Burlington, Mass.). The annular base ring of the BRWstereotactic frame can be attached to the patient's skull. Serial CTsections can be obtained at 3 mm intervals though the (target tissue)region with a graphite rod localizer frame clamped to the base plate. Acomputerized treatment planning program can be run on a VAX 11/780computer (Digital Equipment Corporation, Maynard, MA) using CTcoordinates of the graphite rod images to map between CT space and BRWspace.

[0100] Without wishing to be bound by any particular theory, a mechanismcan be proposed for the therapeutic effects of a method practicedaccording to the present invention. Thus, a neurotoxin, such as abotulinum toxin, can inhibit neuronal exocytosis of several differentCNS neurotransmitters, for example acetylcholine. It is known thatcholinergic neurons are present throughout the brain. Additionally,cholinergic nuclei exist in the basal ganglia or in the basal forebrain,with projections to cerebral regions involved in emotion, behavior, andother cognitive functions. Thus, target tissues for a method within thescope of the present invention can include neurotoxin induced reversibledenervation of brain cholinergic systems, such as basal nuclei orpedunculopontine nucleis. For example, injection or implantation of aneurotoxin to a cholinergic nucleus can result in (1) downregulation ofdopaminergic release from target sites of cholinergic neurons due to theaction of the toxin upon cholinergic terminals projecting into theventral tegmental area from pedunculopontine nucleus; and (2)attenuation of ventral tegmental area output due to the action of thetoxin upon cholinergic neurons projecting to the ventral tegmental area.

[0101] Another mechanism proposed for the present invention includesinhibition of exocytosis of nonacetylcholine neurotransmitters. Forexample, it is believed that once the proteolytic domain of aneurotoxin, such as a botulinum toxin, is incorporated into a neuron,the toxin inhibits release of any neurotransmitter from that neuron.Thus, the neurotoxin may be administered to nuclei containing asubstantial number of dopaminergic neurons so that the neurotoxineffectively inhibits the release of dopamine from those neurons.Similarly, the neurotoxin may be administered to other nuclei such asthe Raphe nuclei to inhibit serotonin exocytosis, the locus ceruleusnuclei to inhibit norepinephrine exocytosis.

[0102] The amount of a neurotoxin selected for intracranialadministration to a target tissue according to the present disclosedinvention can be varied based upon criteria such as the neuropsychiatricdisorder being treated, its severity, the extent of brain tissueinvolvement or to be treated, solubility characteristics of theneurotoxin toxin chosen as well as the age, sex, weight and health ofthe patient. For example, the extent of the area of brain tissueinfluenced is believed to be proportional to the volume of neurotoxininjected, while the quantity of the suppressant effect is, for most doseranges, believed to be proportional to the concentration of neurotoxininjected. Methods for determining the appropriate route ofadministration and dosage are generally determined on a case by casebasis by the attending physician. Such determinations are routine to oneof ordinary skill in the art (see for example, Harrison's Principles ofInternal Medicine (1998), edited by Anthony Fauci et al., 14^(th)edition, published by McGraw Hill).

[0103] A neurotoxin, such as a botulinum toxin, can be intracraniallyadministered according to the present disclosed methods in amounts ofbetween about 10⁻⁴ U/kg to about 1 U/kg. A dose of about 10⁻⁴ U/kg canresult in a suppressant effect if delivered to a small nuclei.Intracranial administration of less than about 10⁻⁴ U/kg does not resultin a significant or lasting therapeutic result. An intracranial dose ofmore than 1 U/kg of a neurotoxin, such as a botulinum toxin, can pose asignificant risk of denervating other afferent or efferent neuronalsystems adjacent to such nuclei. However, it is also believed that theneurons within these nuclei are not as sensitive to the neurotoxin asare neurons at the neuromuscular junction. Accordingly, administrationof a neurotoxin, such as botulinum toxin, to an intracranial targettissue involved in neuropsychiatric disorders effectively reducessymptoms associated with the disorders without causing significantcognitive dysfunction. Thus, the methods of the present inventionprovide more selective treatment with fewer undesirable side effectsthan current systemic therapeutic regimes.

[0104] A preferred range for intracranial administration of a botulinumtoxin, such as botulinum toxin type A, so as to achieve an tremorsuppressant effect in the patient treated is from about 10⁻⁴ U/kg toabout 1 U/kg. Less than about 104² U/kg can result in a relativelyminor, though still observable, neuropsychiatric symptom suppressanteffect. A more preferred range for intracranial administration of abotulinum toxin, such as botulinum toxin type A, so as to achieve thedesired effect in the patient treated is from about 10⁻³ U/kg to about 1U/kg. Less than about 10⁻³ U/kg can result in the desired therapeuticeffect being of less than the optimal or longest possible duration. Amost preferred range for intracranial administration of a botulinumtoxin, such as botulinum toxin type A, so as to achieve a desired tremorsuppressant effect in the patient treated is from about 0.1 units toabout 20 units. Intracranial administration of a botulinum toxin, suchas botulinum toxin type A, in this preferred range can provide dramatictherapeutic success.

[0105] Significantly, a method within the scope of the present inventioncan provide improved patient function. “Improved patient function” canbe defined as an improvement measured by factors such as a reduced pain,reduced time spent in bed, increased ambulation, healthier attitude,more varied lifestyle and/or healing permitted by normal muscle tone.Improved patient function is synonymous with an improved quality of life(QOL). QOL can be assessed using, for example, the known SF-12 or SF-36health survey scoring procedures. SF-36 assesses a patient's physicaland mental health in the eight domains of physical functioning, rolelimitations due to physical problems, social functioning, bodily pain,general mental health, role limitations due to emotional problems,vitality, and general health perceptions. Scores obtained can becompared to published values available for various general and patientpopulations.

[0106] As set forth above, I have discovered that administration of aneurotoxin to a patient suffering from a neuropsychiatric disordersurprisingly provides effective and long lasting treatment of theneuropsychiatric disorder, and reduces the symptoms associated with thedisorder. In its most preferred embodiment, the present invention ispracticed by intracranial injection or implantation of botulinum toxintype A.

EXAMPLES

[0107] The following examples set forth specific methods encompassed bythe present invention to treat a neuropsychiatric disorder and are notintended to limit the scope of the invention.

Example 1

[0108] Intracranial Target Tissue Localization and Methodology

[0109] Stereotactic procedures can be used for precise intracranialadministration of neurotoxin in aqueous form or as an implant to desiredtarget tissue. Thus, intracranial administration of a neurotoxin totreat a neuropsychiatric disorder can be carried out as follows.

[0110] A preliminary MRI scan of the patient can be carried out toobtain the length of the anterior commissure-posterior commissure lineand its orientation to external bony landmarks. The base of the framecan then be aligned to the plane of the anterior commissure-posteriorcommissure line. CT guidance is used and can be supplemented withventriculography. The posterior commissure can be visualized on 2-mm CTslices and used as a reference point to locate the target brain areas.

[0111] Physiological corroboration of target tissue localization can beby use of high and low frequency stimulation through an electrodeaccompanying or incorporated into the long needle syringe used. Athermistor electrode 1.6 mm in diameter with a 2 mm exposed tip can beused (Radionics, Burlington, Mass.). With electrode high frequencystimulation (75 Hz) paraesthetic responses can be elicited in theforearm and hand at 0.5-1.0 V using a Radionics lesion generator(Radionics Radiofrequency Lesion Generator Model RFG3AV). At lowfrequency (5 Hz) activation or disruption of tremor in the affected limboccurred at 2-3 V. With the methods of the present invention, theelectrode is not used to create a lesion.

[0112] Following confirmation of target tissue localization, aneurotoxin can be injected, thereby causing a reversible, chemicaldenervation of the neurons of the target site. A typical injection isthe desired number of units (i.e. about 0.1 to about 5 units of abotulinum toxin type A complex in about 0.1 ml to about 0.5 ml of wateror saline. A low injection volume can be used to minimize toxindiffusion away from target. Typically, the inhibitory effect ofneurotransmitter release can be expected to wear off within about 2-4months. Thus, an alternate neurotoxin format, neurotoxin incorporatedwithin a polymeric implant, can be used to provide controlled,continuous release of therapeutic amount of the toxin at the desiredlocation over a prolonged period. (i.e. from about 1 year to about 6years), thereby obviating the need for repeated toxin injections.

[0113] Several methods can be used for stereotactically guided injectionof a neurotoxin to various intracranial targets, such as thepedunculopontine nuclei to decrease cholinergic neurotransmission, orthe ventral tegmental area to decrease the release of dopamine toalleviate positive symptoms of a neuropsychiatric disorder. For example,a stereotactic magnetic resonance imaging (MRI) method relying onthree-dimensional (3D) T1-weighted images for surgical planning andmultiplanar T2-weighted images for direct visualization of thepedunculopontine nuclei or the ventral tegmental area, coupled withelectrophysiological recording and injection guidance for unilateral orbilateral STN injection can be used. See e.g. Bejjani, B. P., et al.,Bilateral Subthalamic Stimulation for Parkinson's Disease by UsingThree-Dimensional Stereotactic Magnetic Resonance Imaging andElectrophysiological Guidance, J Neurosurg 92(4);615-25:2000.

[0114] Computer-aided atlas-based functional neurosurgery methodologycan be used to accurately and precisely inject the desired neurotoxin orimplant a neurotoxin controlled release implant. Such methodologiespermit three-dimensional display and real-time manipulation of cerebralstructures. Neurosurgical planning with mutually pre-registered multiplebrain atlases in all three orthogonal orientations is therefore possibleand permits increased accuracy of target definition for neurotoxininjection or implantation, reduced time of the surgical procedure bydecreasing the number of tracts, and facilitates planning of moresophisticated trajectories. See e.g. Nowinski W. L. et al.,Computer-Aided Stereotactic Functional Neurosurgery Enhanced by the Useof the Multiple Brain Atlas Database, IEEE Trans Med Imaging19(1);62-69:2000.

Example 2

[0115] Treatment of Schizophrenia With Botulinum Toxin Type A

[0116] A 48 year old male presents with reduced motivation and interestin daily life. The patient indicates that he hears voices. The patientis monitored regularly for six months. The symptoms gradually worsenthroughout the monitoring period, and the patient is diagnosed withschizophrenia. Using CAT scan or MRI assisted stereotaxis, as set forthin Example 1 above, 2 units of a botulinum toxin type A (such as BOTOX®or about 8 units of Dysport®) is injected into the pedunculopontinenucleus. The patient is discharged within 48 hours and with a few (1-7)days enjoys significant improvement of the positive symptoms ofschizophrenia. The positive symptoms of schizophrenia remainsignificantly alleviated for between about 2 to about 6 months. Forextended therapeutic relief, one or more polymeric implantsincorporating a suitable quantity of a botulinum toxin type A can beplaced at the target tissue site.

Example 3

[0117] Treatment of Schizophrenia With Botulinum Toxin Type B

[0118] A 68 year female previously diagnosed and treated forschizophrenia wishes to try a new therapeutic treatment. She seeks theadvice of a physician who recommends botulinum toxin therapy. Using CATscan or MRI assisted stereotaxis, as set forth in Example 1 above, from10 to about 50 units of a botulinum toxin type B preparation (such asNeurobloc® or Innervate™) is injected into the pedunculopontine nuclei.The patient is discharged within 48 hours and with a few (1-7) daysenjoys significant improvement of the positive symptoms. Herhallucinations almost completely disappear. The positive symptoms remainsignificantly alleviated for between about 2 to about 6 months. Forextended therapeutic relief, one or more polymeric implantsincorporating a suitable quantity of a botulinum toxin type B can beplaced at the target tissue site.

Example 4

[0119] Treatment of Schizophrenia With Botulinum Toxin Types C₁-G

[0120] A female aged 71 is admitted with disorder thought patterns andsuffering from auditory and visual hallucinations. From 0.1 to 100 unitsof a botulinum toxin type C₁, D, E, F or G is injected pedunculopontinenuclei to chemically denervate the excitatory cholinergic projection tothe ventral tegmental area. CAT scan or MRI assisted stereotaxis, as setforth in Example 1 above, supplemented by ventriculography is used. Thepatient is discharged within 48 hours and with a few (1-7) days enjoyssignificant remission of tremors which remain significantly alleviatedfor between about 2 to about 6 months. For extended therapeutic relief,one or more polymeric implants incorporating a suitable quantity of abotulinum toxin type C₁, D, E, F or G can be placed at the target tissuesite.

Example 5

[0121] Treatment of Alzheimer's Disease With Botulinum Toxin Type A

[0122] A 85 year old male who has experienced a progressive decline inmental acuity and who no longer remembers how to perform simple tasks,such as brushing teeth, or combing hair is admitted. The patient isotherwise healthy for an 85 year old. He is diagnosed with advancedAlzheimer's disease.

[0123] A suitable stereotactic frame can be applied to the head withlocal anesthetic and ventriculography and stereotactic MRI can beperformed. The stereotactic coordinates of the anterior commissure (AC)and the posterior commissure (PC) can be determined by using thecomputer software in the scanner. PC based software can be used toredraw the sagittal brain maps from the Schaltenbrand and Bailey andSchaltenbrand and Wahren atlases, stretched or shrunk as needed to theAC-PC distance of the patient and ruled in stereotactic coordinates forthe actual application of the frame to the patient's head. The targetsites are selected, their coordinates are read off and appropriate framesettings are made. A burr hole or twist-drill hole can be made at orrostral to the coronal suture in the same sagittal plane as the target.This can facilitate plotting the physiological data used for targetcorroboration since the electrode trajectories traverse a singlesagittal plane.

[0124] Upon microstimulation localization of the stereotactically-MRIguided recording/stimulating needle electrode to the target, aneurotoxin implant can be injected. The implant can comprise aneurotoxin, such as a of botulinum toxin type A, incorporated withinbiodegradable polymeric microspheres or a biodegradable pellet, eitherimplant format containing about 20 total units (about 1 ng) of the toxinwith implant characteristics of continuous release over a period of atleast about four years of a therapeutic level of the toxin at point ofthe implant release site and for a radius of about 2-3 mm on each sideof the locus ceruleus. The implant can release about 1 unit of toxinessentially immediately and further amounts of about one unitcumulatively over subsequent 2-4 months periods.

[0125] Although the patient's loss of memory does not recover fully, thepsychotic symptoms the patient was exhibiting are reduced and remainsubstantially alleviated for between about 2 months to about 6 monthsper toxin injection or for between about 1 to 5 years depending upon theparticular release characteristics of the implant polymer and thequantity of neurotoxin loaded therein.

Example 6

[0126] Treatment of Alzheimer's Disease With Botulinum Toxin Types B-G

[0127] The patient of example 5 above can be equivalently treated usingthe same protocol and approach to target the locus ceruleus with betweenabout 1 unit and about 1000 units of a botulinum toxin type B, C₁, D, E,F or G in aqueous solution or in the form of a suitable neurotoxinimplant. With such a treatment, the psychotic symptoms subside within1-7 days, and remain substantially alleviated for between about 2-6months per toxin injection or for between about 1 to 5 years dependingupon the particular release characteristics of the implant polymer andthe quantity of neurotoxin loaded therein.

Example 7

[0128] Treatment of Mania With Botulinum Toxin Type A

[0129] A 44 year old male is diagnosed with bipolar disorder. An implantcontaining botulinum toxin type A is placed in proximity to the locusceruleus to decrease norepinephrine release. The implant can be eitheran aqueous solution of botulinum toxin type A incorporated withinbiodegradable polymeric microspheres or botulinum toxin type Abiodegradable pellet, either implant format containing about 20 totalunits (about 1 ng) of the toxin with implant characteristics ofcontinuous release over a period of at least about four years of atherapeutic level of the toxin at point of the implant release site andin about 2-3 mm on each side. The implant can release about 1 unit oftoxin essentially immediately and further amounts of about one unitcumulatively over subsequent 2-4 months periods.

[0130] The patient's manic symptoms can subside within 1-7 days, and canremain substantially alleviated for between about 2 months to about 6months per toxin injection or for between about 1 to 5 years dependingupon the particular release characteristics of the implant polymer andthe quantity of neurotoxin loaded therein. Notably, there can besignificant attenuation of hallucinations. In addition, the patient hasa substantially more controlled behavioral pattern.

Example 8

[0131] Treatment of Mania With Botulinum Toxin Types B-G

[0132] The patient of example 7 above can be equivalently treated usingthe same protocol and approach to target with between about 1 unit andabout 1000 units of a botulinum toxin type B, C₁, D, E, F or G inaqueous solution or in the form of a suitable neurotoxin implant. Withsuch a treatment, the symptoms can subside within 1-7 days, and canremain substantially alleviated for between about 2-6 months per toxininjection or for between about 1 to 5 years depending upon theparticular release characteristics of the implant polymer and thequantity of neurotoxin loaded therein.

Example 9

[0133] Treatment of Anxiety With Botulinum Toxin Type A

[0134] A right handed, female patient age 22 presents with a history ofepilepsy. Based upon MRI and a study of EEG recording, a diagnosis oftemporal lobe epilepsy is made. An implant which provides about 5-50units of a neurotoxin (such as a botulinum toxin type A) can be insertedat the anterior part of the temporal lobe, 5-6 cm from the tip of thelobe along the middle temporal gyrus with a unilateral approach to thenondominant, left hemisphere. The epileptic seizures can besubstantially reduced within about 1-7 days, and can remainsubstantially alleviated for between about 2 months to about 6 monthsper toxin injection or for between about 1 to 5 years depending upon theparticular release characteristics of the implant polymer and thequantity of neurotoxin loaded therein.

Example 10

[0135] Treatment of Anxiety With Botulinum Toxin Types B-G

[0136] The patient of example 9 above can be equivalently treated usingthe same protocol and approach to target with between about 1 unit andabout 1000 units of a botulinum toxin type B, C₁, D, E, F or G inaqueous solution or in the form of a suitable neurotoxin implant. Withsuch a treatment, the epileptic seizures can subside within 1-7 days,and can remain substantially alleviated for between about 2-6 months pertoxin injection or for between about 1 to 5 years depending upon theparticular release characteristics of the implant polymer and thequantity of neurotoxin loaded therein.

[0137] It is concluded that neurotoxin injection or implantation of acontrolled release neurotoxin implant according to the methods of thepresent invention, with the aid of 3D MR imaging andelectrophysiological guidance, can be a safe and effective therapy forpatients suffering from various neuropsychiatric disorders, such asschizophrenia, dementia, or mania. Suitable patients include those whoare not responsive or have become unresponsive to systemic agentsutilized to treat such disorders.

[0138] An intracranial neurotoxin administration method for treating aneuropsychiatric disorder according to the invention disclosed hereinhas many benefits and advantages, including the following:

[0139] 1. the symptoms, such as the symptoms associated with hyperactiveneuronal systems of a neuropsychiatric disorder can be dramaticallyreduced.

[0140] 2. the symptoms of a neuropsychiatric disorder can be reduced forfrom about two to about four months per injection of neurotoxin and forfrom about one year to about five years upon use of a controlled releaseneurotoxin implant.

[0141] 3. the injected or implanted neurotoxin exerts an intracranialtarget tissue site specific suppression of neuronal activity.

[0142] 4. the injected or implanted neurotoxin shows little or notendency to diffuse or to be transported away from the intracranialinjection or implantation site.

[0143] 5. few or no significant undesirable side effects occur fromintracranial injection or implantation of the neurotoxin.

[0144] 6. the amount of neurotoxin injected intracranially can beconsiderably less than the amount of the same neurotoxin required byother routes of administration (i.e. intramuscular, intrasphincter, oralor parenteral) to achieve a comparable suppressant effect.

[0145] 7. the suppressant effects of the present methods can result inthe desirable side effects of greater patient mobility, a more positiveattitude, and an improved quality of life.

[0146] 8. high, therapeutic doses of a neurotoxin can be delivered to anintracranial target tissue over a prolonged period without systemictoxicity.

[0147] Although the present invention has been described in detail withregard to certain preferred methods, other embodiments, versions, andmodifications within the scope of the present invention are possible.For example, a wide variety of neurotoxins can be effectively used inthe methods of the present invention. Additionally, the presentinvention includes intracranial administration methods wherein two ormore neurotoxins, such as two or more botulinum toxins, are administeredconcurrently or consecutively. For example, botulinum toxin type A canbe administered intracranially until a loss of clinical response orneutralizing antibodies develop, followed by administration of botulinumtoxin type B. Furthermore, non-neurotoxin compounds can beintracranially administered prior to, concurrently with or subsequent toadministration of the neurotoxin to provide adjunct effect such asenhanced or a more rapid onset of suppression before the neurotoxin,such as a botulinum toxin, begins to exert its more long lastingsuppressant effect.

[0148] My invention also includes within its scope the use of aneurotoxin, such as a botulinum toxin, in the preparation of amedicament for the treatment of a neuropsychiatric disorder, byintracranial administration of the neurotoxin.

[0149] All references, articles, patents, applications and publicationsset forth above are incorporated herein by reference in theirentireties.

[0150] Accordingly, the spirit and scope of the following claims shouldnot be limited to the descriptions of the preferred embodiments setforth above.

I claim:
 1. A method for alleviating a symptom of a neuropsychiatricdisorder, the method comprising a step of administering to a patientwith a symptom of a neuropsychiatric disorder a therapeuticallyeffective amount of a Clostridial neurotoxin, wherein the Clostridialneurotoxin is administered to an intracranial site which is associatedwith the symptom of the neuropsychiatric disorder, thereby alleviatingthe symptom of the neuropsychiatric disorder.
 2. The method of claim 1,wherein the neurotoxin is made by a bacterium selected from the groupconsisting of Clostridium botulinum, Clostridium butyricum andClostridium beratti.
 3. The method of claim 1, wherein the neurotoxin isa botulinum toxin.
 4. The method of claim 3, wherein the botulinum toxinis selected from the group consisting of botulinum toxin types A, B, C₁,D, E, F and G.
 5. The method of claim 3, wherein the botulinum toxin isbotulinum toxin type A.
 6. The method of claim 3, wherein the botulinumtoxin is administered in an amount of between about 10⁻⁴ U/kg and about1 U/kg.
 7. The method of claim 1, wherein the symptom alleviating effectpersists for between about 1 month and about 5 years.
 8. The method ofclaim 1, wherein the neurotoxin is administered to a lower brain region.9. The method of claim 1, wherein the neurotoxin is administered to apontine region
 10. The method of claim 1, wherein the Clostridialneurotoxin is a recombinantly produced Clostridial neurotoxin thereof.11. The method of claim 1, wherein the intracranial administration stepcomprises implantation of a botulinum toxin containing controlledrelease system.
 12. The method of claim 1, wherein the administration ofthe neurotoxin alleviates a symptom of the neuropsychiatric disorderthat is associated with hyperactive neurotransmitter release fromneurons.
 13. The method of claim 1, wherein administering theClostridial neurotoxin restores a balance between at least two neuronalsystems that release different neurotransmitters, thereby alleviatingthe symptom of the neuropsychiatric disorder.
 14. The method of claim 1,wherein administering the Clostridial neurotoxin decreases anacetylcholine release from a cholinergic neuron, thereby alleviating thesymptom of the neuropsychiatric disorder.
 15. The method of claim 1,wherein administering the Clostridial neurotoxin decreases a dopaminerelease from a dopaminergic neuron, thereby alleviating the symptom ofthe neuropsychiatric disorder.
 16. The method of claim 1, whereinadministering of the Clostridial neurotoxin decreases a norepinephrinerelease from a noradrenergic neuron, thereby alleviating the symptom ofthe neuropsychiatric disorder.
 17. A method for treating a symptom of aneuropsychiatric disorder, the method comprising a step of administeringto a patient with a symptom of a neuropsychiatric disorder atherapeutically effective amount of a botulinum toxin, wherein thebotulinum toxin is administered to an intracranial site which isassociated with the symptom of the neuropsychiatric disorder, therebytreating the symptom of the neuropsychiatric disorder.
 18. The method ofclaim 17, wherein the botulinum toxin is botulinum toxin type A
 19. Themethod of claim 17, wherein the neuropsychiatric disorder is selectedfrom the group consisting of schizophrenia, Alzheimer's disease, mania,and anxiety.
 20. A method for treating a neuropsychiatric disorder, themethod comprising a step of administering to a patient with a symptom ofa neuropsychiatric disorder a therapeutically effective amount of abotulinum toxin, wherein the botulinum toxin is administered to anintracranial site which is associated with the symptom of theneuropsychiatric disorder, thereby treating the symptom of theneuropsychiatric disorder by reducing neurotransmitter release fromneurons contributing to the symptom of the neuropsychiatric disorderwithin about four months after the administration of the botulinumtoxin.
 21. A method for treating schizophrenia, the method comprising astep of administering to a patient with schizophrenia a therapeuticallyeffective amount of a botulinum toxin, wherein the botulinum toxin isadministered to an intracranial site which is associated with a symptomof schizophrenia, thereby treating schizophrenia.
 22. The method ofclaim 21, wherein the botulinum toxin is botulinum toxin type A
 23. Amethod for alleviating a symptom of a neuropsychiatric disorder, themethod comprising the step of administering to a peripheral site of apatient with a symptom of a neuropsychiatric disorder a therapeuticallyeffective amount of a Clostridial neurotoxin.